A remark can be heard and caught but never seen. This is the answer to a popular riddle, with which the person posing the question tries to stump the listener.
A riddle is a question or statement so framed as to exercise one's ingenuity in answering it or discovering its meaning. It is also defined as a conundrum, puzzling question, problem or matter. The word appeared in speech and writing before the year 1000 AD, and is derived from the Middle English word "redel" and the Old English word "r?dels," meaning counsel, opinion or imagination. Perhaps the most famous riddle comes from the play "Oedipus," in which the Sphinx forces passersby to answer a riddle or face death.